128 results found
Blanc M, Moura D, Alibert Y, et al., 2005, Tracing the origins of the solar system, Pages: 213-224, ISSN: 0379-6566
All contemporary objects of our Solar System emerged from a solar nebula which existed 4.5 billion years ago, and whose dynamical and thermo-chemical evolution led to the condensation of solids, then to the emergence of different types of planetesimals, and finally to the accretion of solid cores and to the formation of our planets. Space exploration makes it possible today to visit the different classes of solar system objects and retrieve key information which can help us to trace back the evolutionary path of the solar system, from its origins in the Solar Nebula to its present configuration and the likely development of habitats in planetary objects. We propose three un-ordered priorities for the space programme in this perspective: 1 - access to remaining pristine material in the solar system (interplanetary dust and small bodies); 2 - in-depth exploration of the systems of giant planets; 3 - in-situ analysis of some of the physical mechanisms relevant to planetary formation in the contemporary rings and plasma environments of giant planets. This research subject, which strongly connects our solar system and its objects to exoplanets and other planetary systems, is a very promising contribution to the progressive build-up of a synthetic view of their formation and evolution scenarios. It is a central element in the build-up of a "Cosmic Vision" of our own solar system. We show how the major scientific questions related to this broad theme can be translated into specific mission targets and measurement objectives, and grouped into a "short list" of key space missions. This short list forms an ideal basis to elaborate a multi-decadal endeavour to explore the outer solar system. Most of these missions, while addressing the specific question of solar system origin, also are of major interest for comparative planetology and exo-astrobiology. While a few can be implemented in a purely European context, most of these missions can be accomplished on
Ivchenko N, Rees MH, Lanchester BS, et al., 2004, Observation of O<sup>+</sup> (<sup>4</sup>P-<sup>4</sup>D<sup>0</sup>) lines in electron aurora over Svalbard, Annales Geophysicae, Vol: 22, Pages: 2805-2817, ISSN: 0992-7689
This work reports on observations of 0+ lines in aurora over Svalbard, Norway. The Spectrographic Imaging Facility measures auroral spectra in three wavelength intervals (Hβ, N+2 1N(0,2) and N+2 1N(1,3) . The oxygen ion 4P-4D0 multiplet (4639-4696 Å) is blended with the N+2 1N(1,3 band. It is found that in electron aurora, the brightness of this multiplet, is on average, about 0. 1 of the N+2 1N(0,2) total brightness. A joint optical and incoherent scatter radar study of an electron aurora event shows that the ratio is enhanced when the ionisation in the upper E-layer (140-190 km) is significant with respect to the E-layer peak below 130 km. Rayed arcs were observed on one such occasion, whereas on other occasions the auroral intensity was below the threshold of the imager. A one-dimensional electron transport model is used to estimate the cross section for production of the multiplet in electron collisions, yielding 0. 18 × 10-18 cm2. © European Geosciences Union 2004.
Galand M, Baumgardner J, Pallamraju D, et al., 2004, Spectral imaging of proton aurora and twilight at Tromso, Norway, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 109, ISSN: 2169-9380
Ivchenko N, Galand M, Lanchester BS, et al., 2004, Observation of O(+4)P-(4)D(0) lines in proton aurora over Svalbard, GEOPHYSICAL RESEARCH LETTERS, Vol: 31, ISSN: 0094-8276
Galand M, Lummerzheim D, 2004, Contribution of proton precipitation to space-based auroral FUV observations, JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Vol: 109, ISSN: 2169-9380
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